The present invention relates to an apparatus for detecting crank angle positions in an internal combustion engine.
A well known apparatus for detecting crank angle positions in an internal combustion engine is as disclosed in U.S. Pat. No. 2,596,581. This apparatus has a first rotator with magnetic protrusions provided on the crankshaft at regular intervals and, on the camshaft, is a second rotator with magnetic protrusions provided at irregular intervals. This apparatus for detecting crank angle positions detects and counts the number of crank pulses and cam pulses generated by the passing of the magnetic protrusions provided on the first rotator and the second rotator and determines the angle position of the crankshaft in an internal combustion engine by the corresponding number of pulses.
However, such a conventional apparatus for detecting crank angle position in an internal combustion engine may take a long time before it determines the stroke because some angle positions of the crankshaft at the time the engine is started require the crankshaft to rotate more than 360xc2x0 before a stage number can be determined.
The present invention has been made in consideration of the aforementioned background. The object of the present invention is to provide an apparatus for detecting crank angle positions in an internal combustion engine which can determine the stroke of an internal combustion engine in a short time.
An apparatus for detecting crank angle position in an internal combustion engine according to the present invention is an apparatus for detecting the rotational angle positions of the crankshaft of the internal combustion engine having a crankshaft and a camshaft which interlocks with the crankshaft at a predetermined revolution ratio. A first rotator and a second rotator, which interlock with the crankshaft and the camshaft respectively, both have a plurality of detectable parts in the rotation direction. The spaces between the adjoining detectable parts on the first rotator are nearly equal to each other. Sequences or permutations each consisting of at least two consecutive or neighboring spaces between the detectable parts in the rotation direction on the second rotator are different from each other.
That is, according to the features of the present invention, the stroke of an internal combustion engine can be determined in a short time because the detectable parts on the first rotator are provided so that adjoining spaces are nearly equal to each other, while the detectable parts on the second rotator are provided so that sequences of at least two adjoining angular spaces in the rotation direction are different from each other.